66/80CC Sprocket problem

The-Dullahan · Feb 18, 2015

Hey, everyone. This is actually my first post here and I am rather new to the world of motorized bicycles.

That said, let me get right down to the issue I am having. I am using a generic Chinese engine kit (not what I'd normally choose, but I felt that it would be a good starting point to introduce myself to this with and given local laws, where anything over 50CC is illegal, I felt I should try to be a bit more low key this go around) and I've gotten my build to the point where I have to put the engine on it. Yay. The problem I am having is actually getting the chain on the drive sprocket on the engine.

I know how to dismantle the opposite side of the engine and manually spin the sprocket, I know how to spin the sprocket from the side it's on as well, using a socket. That is not the issue I am having.

It's like the chain does not want to FIT the sprocket. I can get four links onto the sprocket before the fifth one just sort of glides over the teeth.

I COULD manually force all of the teeth in place, but before I go doing any damage to it by attempting to run the engine that way, I figured I'd try to solve it with Google.

So Google has no information on what I'm asking, so I've come here.

Basically, my idea is this: I have two of these engines. One as a parts engine, because when it arrived at my house it was thoroughly destroyed and one solid engine (presently mounted on the bike)

I am thinking that perhaps I can remove the sprocket on my parts engine and place it onto the engine on my bike. The problem is, I have no idea how these engines are assembled internally.

I don't have a gear puller nearly small enough to pull the gear off of the shaft. Youtube tells me it is possible to hammer the entire assembly out from the opposite side (Using a block of wood, naturally).

What about reinstallation? Do I just hammer it back through from the sprocket side?

Is there an easier way to remove just the sprocket, rather than the entire shaft?

2door · Feb 18, 2015

Welcome to the forum. We're sorry you're having these problems so let's see if we can help out.

To remove the sprocket you should have a special tool that comes with most, not all, kits. It threads into the sprocket and becomes a puller when you tighten it. It can be removed with a gear puller but the tool I mentioned makes it much easier.

Now to your chain problem. Please don't assume we're talking down to you but we have no way of knowing your mechanical skills or background. From what you're saying the chain pitch seems to differ from the sprocket tooth spacing. This isn't a common problem, especially with most engine kits but I have seen kits come with regular bicycle chain that doesn't work. Look at your chain and see if you see 415 stamped somewhere on a side plate. That's a metric chain size supplied with most kits.

There are reports of mal-formed sprocket teeth that need to be 'dressed' or smoothed a little to allow them to engage the roller chain. In that case they can be ground, sanded or reconfigured with the proper tools. I don't believe this is your problem. My gut feeling is that you might not have the sprockets aligned and the chain is being pulled off to one side or the other.
Both drive and driven, engine and rear wheel, sprockets MUST be in line with each other as well as the chain tensioner wheel.

Could you possible provide a picture of what you are encountering. That might help us make more recommendations.
And I'm sure you'll get more replies so be patient and hear what others have to say.

Tom

Mannhouse51 · Feb 18, 2015

My last kit did the same thing...the kit provided chain just would not go around the engine sprocket, it was very tight. It seemed to fit the large sprocket o.k. I went to the local hardware store and bought some chain...and that worked fine..LOL kinda strange

cannonball2 · Feb 18, 2015

I just did an install for a neighbor and had a similar issue. Turns out the engines sprocket was improperly machined. It basically destroyed the chain in short order. We swapped on a good used sprocket and chain I had and had no further issues.
Looking at the sprocket it became apparent that four of the teeth were machined out of line.

The-Dullahan · Feb 18, 2015

Trying to post an additional post here, but it isn't appearing?

Okay, apparently my last post didn't go through...let's try doing it again:

I purchased the tool from Amazon. Comes with a new sprocket anyhow (so at least I'll have two working sprockets, should I decide to rebuild the parts engine)

Too dark to get a photograph this late, but I managed to get a crappy mobile phone photo of the bike itself. Presently has no throttle or fuel line, but the since chain isn't mating or disengaging from the sprocket correctly anyhow, I'm not about to try riding it, so I'll handle those next time I have a free moment.

The-Dullahan · Feb 18, 2015

I keep trying to post a response to this, but it's not working.

I have the correct 415 chain, yes, it just seems to be the sprocket on my complete engine that is the problem. It does not mate or disengage properly. It literally glides over the sprocket on the parts engine without a problem. Misalignment cannot be the cause, because even when simply threading it by hand, without the chain actually being fitted onto the rear wheel, the chain will not connect with the sprocket properly. It just sort of bunches up and if manually forced between the teeth as intended, it becomes stuck and requires a good bit of force to remove. Again, it goes over the spare sprocket without a problem.

Anyhow, I have ordered the tool online. Apparently, if I share a photo from Photobucket to this page, the post automatically gets deleted, so no pictures tonight.

maniac57 · Feb 19, 2015

I have found several motors that needed the tips on the engine sprocket reworked to allow chain to run free. The tips are too wide and need to be sharpened a bit. Go easy though.
Just touch up the tips until the chain fits properly.
Or buy a new sprocket.

crassius · Feb 19, 2015

many chains are now 'heavy duty' 415 which means the rollers are a bit wider that standard

some of the cheaper sprockets are machine stamped which leaves the tips of the teeth wide & flat on top so that the roller won't drop into the gap

file the sides of the tooth tips until there is more room

GoreWound · Feb 19, 2015

subforum link
that section of the forum has a huge list of sticky post tutorials and guides, good reading even if you don't need the help.

by the sound of things you've already gotten the advice you need, I just wanted to add that sometimes the chain rubs inside the case, not much can be done about that unfortunately (you can grind away some of the casting that's in the way) but you might be having a problem with that. my bike had the chain almost locked by a slightly bulged bit of casting on the clutch actuator cover when I first put it together.

also as an aside: your bike looks super cool! I love the colours, I love your gas tank, and I love your saddle-box!
good luck getting it running, your bike already looks super-fine!

The-Dullahan · Feb 19, 2015

I had suspected similarly about the production quality of the sprockets. By the time my tool arrives, I will also have another spare sprocket, but I had planned to try to file the one presently on the engine down as well, simply because it never hurts to have a functional spare.

GorWound. Thank you. This is my second "Zero Dollar Budget/What I Had Laying Around The Garage" build. The first was not motorized.

Intrepid Wheelwoman · Feb 19, 2015

Ah yes Guinness, - I can see you're a properly brought up lad

GoreWound · Feb 19, 2015

The-Dullahan, you clearly have an eye for bikes.

KCvale · Feb 19, 2015

GoreWound said:
I just wanted to add that sometimes the chain rubs inside the case, not much can be done about that unfortunately (you can grind away some of the casting that's in the way) but you might be having a problem with that.

Yep.
I got a few 66cc engines from gasbike that were based on the GT5 but they changed from a sprocket for 410 chain to 415 and it hit the case.
They have fixed that but it has been a know issue.

The thing is, when you buy a $100 kit they are that cheap for a reason and it's not greed, it's ever lower quality parts throughout and why I stick with the $160-$185 kits.

It's all the little **** that adds up when you build a lot of bikes and you just can't screw with warped sprockets, tiny crappy leaky tanks, poor mounts and sub-standard ignition, etc.

I have a whole a shelf with a 5" tall stack of crap rear sprockets from OP builds and the list goes on.
Drill through the frame 1 bolt front mounts, the wimpy flat dual U-bolt front mount 'better' front mount...
All crap.

Save a dollar now or spend $10 more as stuff fails.
I don't dick around, I don't want to see returns for repairs and do a pretty good of rarely seeing any if that says anything.

Granted if you have no money to start with bummer for you.
Really, there are no more shortcuts to make something sound and reliable than already around for less.

A turd will always be a turd no matter what you throw at it is my opinion which has nothing to do with your problem but just in general.

You'll get your chain issue handled with more work and money and then the next issue will come up I suspect.

Welcome to motorized bicycles on the cheap to start as it don't end up that way when you get to where you are spending more time walking it home and buying new parts than riding.

Just a tip for other builders.

2door · Feb 19, 2015

Dullahan,
I brightened up your phone camera photo so folks can get a better look at your bike. Hope you don't mind.

I have to question the 'wrapping' is see on the frame. What is it and what's it for?

Tom

The-Dullahan · Feb 20, 2015

Generic Friction Tape...From...some brand. 3M Maybe?

Keeps the paint from being scratched. The most notable place on the motorized bike is around the frame, near the seat. That is because that is where I would wrap a chain around it, were I to leave it someplace (I do not generally trust people). While it is less important on the other bike (The black/green one), as it is flat black and anyone with no experience at all can repaint that with even a generic spraybomb/rattlecan/whatever other term you prefer, that bike has it as well. Possibly because I didn't have a proper chain for it and used a pair of handcuffs (Which I am pretty sure are on the bike in those photos)

Motorized bicycle was stripped, primed, painted, clearcoated then buffed (with wetsanding between every step) I really don't care about the paintjob, but figured I should give it at least the care that the flat black one had or else all of the bodywork and paint time was for naught. Some people prefer rubber padding for this, but I've found that the friction tape works just as well and unlike rubber strips, I happen to have a plethora of tape on hand, at least most days.

The-Dullahan · Feb 20, 2015

Intrepid Wheelwoman said:
Ah yes Guinness, - I can see you're a properly brought up lad

Built with parts I had on hand. Bottle Opener, vintage Pennsylvania license plate (Not actually a motorcycle plate, because the motorboat plat matched the colour better) and a crate from National Powder Company (Gelignite/Gelatin Explosive) Headlight off of a...something found in a trainyard...not sure of the origin, but it's a Monogram product and the battery box (located inside of the cargo crate) is a modified artillery shell canister.

Rural PA, specifically the part I come from (Where all the little immigrant Irish kids live) was home to the birthplace of the Unions and of course, through association, the Molly Maguires. That was the origin of several companies (more than breweries, foundries, and mines we are so famous for back home. However, the association of the organized Irish Immigrants with these companies and industries in Pennsylvania was also the thing that inevitably affected their relationships with the UK (not that they had business there).

Even today, though far outdated, Gelignite is difficult to acquire anywhere under English Rule, via a law enacted when the British realized how easy the Irish were getting it overseas by their brothers. Same reason Armalites were outlawed in Boston.

Not to get into politics. That's just how that bike was made. I've had people ask "what the theme" would be on the newer bike (the motorized one) when I said I would build it. I responded by asking why it should have a theme. That is apparently the "theme" that most people thought the pedalbike had. In reality, despite my connections through ethnic and cultural relation to the collective history of those items, that bike was literally a "whatever is lying around" bike. It started life as an Amstel Lite themed bike manufactured by a company I had at the time, never heard of, known as "SixThreeZero".

The motorized one was originally (during my ownership) as a rusty, damaged Huffy Cranbrook (Possibly run into with a car?) that was painted in some ugly metallic beige and black colour scheme.

mapbike · Feb 20, 2015

The-Dullahan said:
I had suspected similarly about the production quality of the sprockets. By the time my tool arrives, I will also have another spare sprocket, but I had planned to try to file the one presently on the engine down as well, simply because it never hurts to have a functional spare.

GorWound. Thank you. This is my second "Zero Dollar Budget/What I Had Laying Around The Garage" build. The first was not motorized.

nice bike, I like it....

mapbike · Feb 20, 2015

KCvale said:
Yep.
I got a few 66cc engines from gasbike that were based on the GT5 but they changed from a sprocket for 410 chain to 415 and it hit the case.
They have fixed that but it has been a know issue.

The thing is, when you buy a $100 kit they are that cheap for a reason and it's not greed, it's ever lower quality parts throughout and why I stick with the $160-$185 kits.

It's all the little **** that adds up when you build a lot of bikes and you just can't screw with warped sprockets, tiny crappy leaky tanks, poor mounts and sub-standard ignition, etc.

I have a whole a shelf with a 5" tall stack of crap rear sprockets from OP builds and the list goes on.
Drill through the frame 1 bolt front mounts, the wimpy flat dual U-bolt front mount 'better' front mount...
All crap.

Save a dollar now or spend $10 more as stuff fails.
I don't dick around, I don't want to see returns for repairs and do a pretty good of rarely seeing any if that says anything.

Granted if you have no money to start with bummer for you.
Really, there are no more shortcuts to make something sound and reliable than already around for less.

A turd will always be a turd no matter what you throw at it is my opinion which has nothing to do with your problem but just in general.

You'll get your chain issue handled with more work and money and then the next issue will come up I suspect.

Welcome to motorized bicycles on the cheap to start as it don't end up that way when you get to where you are spending more time walking it home and buying new parts than riding.

Just a tip for other builders.

LOL........!!!!!

Plugging the gasebike kits again are we....?

So what your saying here is that the manufacturer of the kits you buy make all their own cdi's, tanks, sprockets, etc and that all the other kits are put together from a bunch of junk parts?

Personally, all the parts you mentioned here look the same to me, all the CDI units look the same, that tanks usually fail do to the i staller over tightening the hardware which can pull the stud hard enough to crack the tank around the weld on any of them.

out of all the engines I have and have had I've yet to get a bad sprocket.

Not hating on the kits you use KC but you always put down any and everything anyone else has or uses unless its what you like, use and support.

From what Ive seen the overall quality of the engine is the difference it the kits and not so much the hardware, some of the cheaper kits have very good running and good balan ed engines and some dont, I do think the GT5 geometry engines are really good, but there are more than one vendor to get them from and many people have gotten good ones from a couple of the ebay sellers for $130

The-Dullahan · Feb 20, 2015

Seems relevant to end the debate that is starting:

The engine that came with the chain is the one with the sprocket that fits the chain perfectly. It is my second engine which has this problem. Not sure about the different "kits" but the engine and chain I got together actually seem to function great together, which is why I will be switching the sprockets from that engine and the engine I am using now.

mapbike · Feb 20, 2015

The-Dullahan said:
Seems relevant to end the debate that is starting:

The engine that came with the chain is the one with the sprocket that fits the chain perfectly. It is my second engine which has this problem. Not sure about the different "kits" but the engine and chain I got together actually seem to function great together, which is why I will be switching the sprockets from that engine and the engine I am using now.

Thats great, as long as you get it worked out, thats all that matters, these engi es and kit parts can be a pain in the neck sometimes but none of it is very expensive or hard to get lined out once the issue is narrowed down, just part of this fun little hobby in my opinion.

Keep us up to date on how well it all turns out for you. dnut

66/80CC Sprocket problem

New Member

Moderator

New Member

Well-Known Member

New Member

New Member

Old, Fat, and still faster than you

Well-Known Member

New Member

New Member

New Member

New Member

Attachments

Well-Known Member

Moderator

Attachments

New Member

New Member

Well-Known Member

Well-Known Member

New Member

Well-Known Member